REBOL [ Title: "Permute" Date: 3-Jul-2002 Name: 'Permute Version: 1.0.0 File: %Permute.r Author: "Andrew Martin" Purpose: "Permutes a matrix." eMail: %Al--Bri--xtra--co--nz Web: http://valley.150m.com Example: { ^-^-Permute [[-1 0 1] [-1 0 1]] ^-^-;== [[-1 -1] [-1 0] [-1 1] [0 -1] [0 0] [0 1] [1 -1] [1 0] [1 1]] ^-^-} library: [ level: 'beginner platform: none type: 'tool domain: 'math tested-under: none support: none license: none see-also: none ] ] make object! [ Permute2: function [Matrix [block!]][Permutations][ Permutations: make block! (length? Matrix/1) * (length? Matrix/2) foreach M1 Matrix/1 [ foreach M2 Matrix/2 [ repend/only Permutations [M1 M2] ] ] Permutations ] Permute3: function [Matrix [block!]][Permutations][ Permutations: make block! (length? Matrix/1) * (length? Matrix/2) * (length? Matrix/3) foreach M1 Matrix/1 [ foreach M2 Matrix/2 [ foreach M3 Matrix/3 [ repend/only Permutations [M1 M2 M3] ] ] ] Permutations ] Permute4: function [Matrix [block!]][Permutations][ Permutations: make block! (length? Matrix/1) * (length? Matrix/2) * (length? Matrix/3) * (length? Matrix/4) foreach M1 Matrix/1 [ foreach M2 Matrix/2 [ foreach M3 Matrix/3 [ foreach M4 Matrix/4 [ repend/only Permutations [M1 M2 M3 M4] ] ] ] ] Permutations ] Merge: function [Matrix [block!]][][ map/only Matrix func [Item][join Item/1 Item/2] ] set 'Permute func [[catch] Matrix [block!]][ switch/default length? Matrix [ 2 [Permute2 Matrix] 3 [Permute3 Matrix] 4 [Permute4 Matrix] 5 [Merge transpose reduce [Permute3 Matrix Permute2 at Matrix 4]] 6 [Merge transpose reduce [Permute3 Matrix Permute3 at Matrix 4]] 7 [Merge transpose reduce [Permute3 Matrix Permute4 at Matrix 4]] 8 [Merge transpose reduce [Permute4 Matrix Permute4 at Matrix 5]] ][ throw make error! [script out-of-range Matrix] ] ] ]